40° C idle to ~90° C under load... is this normal?

[Mr Glynn]

Hello,
I have an E6750 processor in an MSI Neo2-FR motherboard with the stock Intel heatsink/fan. I have overclocked it using the BIOS from 2.66 ghz to about 3 ghz (375 fsb * multiplier of 8 ). It idles around 40° to 45° Celcius (according to Speedfan 4.33). I have tried to do stability testing with Orthos and Prime95 but the CPU temp jumps up to 90° c (I have stopped the tests before it goes any higher). This doesn't seem normal to me considering the load temp is more than 2x the idle temp. Do I need a better HS/F or is something else probably causing this?

Another question: there is a jumper on the motherboard to set the fsb from 200 mhz to 266 mhz to 333 mhz. Does this actually affect the fsb since I have it set at 375 mhz in the BIOS?

I am a bit of a newbie at this point so if I have left out any relevant information please tell me.

Thanks,
Rob

[Heartbreak one]

Try to install CoreTemp, it uses the CPUs own sensors to monitor heat. You can get it here.

http://www.alcpu.com/CoreTemp/

If CoreTemp shows the same temps. then you better get a new cooler or clock the CPU back to the standard speed.

[Mr Glynn]

Thanks for the reply. I am definitely getting a better hsf. I installed coretemp and the readings are the same... the temps at 3.0 ghz are almost the same as they were at 2.66 ghz. I haven't increased any voltages at all... but cpu-z says "Core VID 1.338 V". I haven't been able to find a definitive default voltage for the E6750, but could this be higher than it needs to be and therefore creating more heat than it should be?

[Heartbreak one]

Your voltage is pretty high...
CPU-Z shows that my E4400 runs @ 1.288V (1.2V when SpeedStep is activated) I don't know what the stock VCore is for E6750, but it should not be much higher than that I got

[Mr Glynn]

I have all of the voltages set to the minimums that the BIOS will allow:

CPU Voltage: 1.2875
Memory Voltage: 1.8
VTT FSB Voltage: 1.175
NB Voltage: 1.250
SB I/O Power: 1.5
SB Core Power: 1.05

The BIOS tells me the CPU voltage is 1.2875, but Core temp and CPU-z are saying Core VID = 1.338. What is going on here?

[Unzlbunzl]

the voltage difference isnt high enough to cause the chip to get so hot. try touching the base of your heatsink when you read 90°C - if you don't burn your fingers the reading should be wrong. if they are really that hot, your heatsink is probably not mounted correctly

[debs3759]

The processor should work at between 0.85V - 1.5V. See http://www.cpu-world.com/CPUs/Core_2/Intel-Core%202%20Duo%20E6750%20HH80557PJ0674MG%20(BX80557E6750).html for full details...

1.2875/1.288V seems reasonable if I am properly understanding the figures. 1.338 also seems to be in the safe range. The mid-point of the voltage range described on this site (the above link) is 1.175V, so the difference isn't as bad as it might appear, and seems unlikely to be the problem.

Note also that the page above also indicates that the safe operating temperature range is 5-72 C. You are wise not to let it keep running at such a high temperature

[Heartbreak one]

I got two questions:

1. Is the max operating temp the Tcase or Tjunction temp.? (for C2D)
My E4400 has the L2 revision. It has about 15*C difference between Tcase and Tjunction temps.

2. What is revision and stepping?

Thanks

[debs3759]

I can't answer the first question as I don't have datasheets that modern yet (haven't been downloading many lately).

Revision and stepping are the same thing, and refer to which version of the core you have. That means that L2 is both the revision and the stepping (depending who you ask, it can be called either).

I'm not sure if you needed more info than that, so here goes...

Each stepping of a processor, theoretically (but not always!) fixes bugs from a previous revision. Sometimes a new feature is added, or even a new bug. Sites like this, alongside the Intel docs (and spec updates, for differences between steppings) are the best place to get info on exactly what differences there are.

[gshv]

[Mr Glynn]

Update - I've done some experimentation with the heatsink and even at 90 degrees celsius it feels only slightly warmer than room temperature. I have a feeling it is not properly installed (its got one of those pin "pop in and twist" mounting systems).

[Heartbreak one]

Thx Gennadiy and debs3759